Data of which real time properties are required, for example, digital moving data must be transmitted at high speed. Therefore, in recent years, serial interfaces comprising the function of real time transmission, for example, cables and connectors conforming to an IEEE 1394 (Institute of Electrical and Electronics Engineers 1394) high-speed serial bus standard have been employed.
In an AV (Audio-Visual) apparatus such as a TV (Television) receiver, for example, receptacle type connectors are respectively arranged on a front surface and a rear surface of the apparatus, to respectively connect to the receptacle type connectors corresponding plug type connectors connected to a video camera, for example.
In this case, when I/O (input-output) boards are respectively provided in a front part and a rear part of the apparatus, and the boards are respectively equipped with the receptacle type connectors on the front and reverse surfaces, the manufacturing cost rises.
Therefore, it is considered that the board is arranged only in the rear part of the apparatus, and the board in the rear part and the receptacle type connector arranged on the front surface are connected to each other by a relay cable. In this case, however, noises radiated from the relay cable may affect components in the apparatus.
Therefore, it is also considered that a shielding line in the relay cable is connected to a ground line in the board. In the case, however, noises are radiated to the ground line in the board, so that the impedance matching of each of the lines in the board may be destroyed.
In a game apparatus that performs image formation, for example, the same type of problems also arises in a case where an I/O board arranged in the apparatus and a receptacle type connector are connected to each other by a relay cable.
The present invention has been made in view of the foregoing problems and has for its object to provide a transmission device capable of reducing radiation noises in an apparatus.